Rear sight mechanism for small arms



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SSB-252% J. D.PEDERSEN REAR SIGHT MEcHANIsM FOR SMALL ARMs original Filed June's'. i927 wmwm 55% @wie www;

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Patented Dec. 1, 1931 UNITED STATES l uit JOHN n. rEnERsEN, or JACKSON, WYOMING REAR SIGHT MEG'HANISM FOR SMALL ARMS Original application filed .Tune 9, 1927, Serial No. 197,718, now Patent No. 1,737,974, dated December 3, 1929, and in Great Britain March 20, 1928. Divided and this application led J'uly 31, 1929.

Serial No. 382,393.

This application is a division of my cpending application Serial No. 197,718, filed June 9, 1927, now Patent 1,737,974 granted Dec. 3, 1929.

f This invention relates to a rear sight mechanism for small arms and has for its object an improved and simpliiied construction of rugged character for such mechanism, more particularly adapting it for use on field service riies.

According to one feature of the invention, the mounting of the adjustable mechanism takes its support from a rigid upstanding4 or integral part of the gun frame which is preferably, although not necessarily, symmetrically disposed at each side of the sighting axis and of high enough extent to protect said mechanism from injury by rough or careless handling of the gun.

A further feature of improvement resides in the means for effecting the vertical adj ustment of the elevation slide which consists of a peripherally threaded thumb nut carried in the slide and protruding therefrom at one side for operation by the fingers while its other side is submerged in the mechanism for meshing with a coacting rack, the latter being adjustably fixed on the gun for the proper setting of the zero position of the elevation slide. 'llhemyynippluagg,Sldetllyng @arearsshtis,preferably.heusedinsturdy surrounding strpcture of the elevation slide andwtiusmguarded against possible injury.

Still further features of improvement contributing to the common end of providing a well protected mechanism for easy manipulation and accurate adjustment for fine shooting will become apparent from the following 40 more detailed description.

Referring generally to the drawings:

Fig. 1 is a side elevation of a rifle upon which the present rear sight mechanism is mounted;

Fig. 2 is a rear view of the sight mechanism;

Fig. 3 is a top plan View of the same;

Fig. 4 is a vertical section of said sight mechanism on line 4 4 of Fig. 2, showing the 50 spindle detent in full and in addition parts of the receiver, stock and trigger guard frame;

Fig. 5 is an underside View of the elevation slide;

Fig. 6 is a detached view of the sight-nut 55 spindle; and

Fig. 7 is a detached view of the sight-nut key stem.

Referring to Figs. 1 and 2, the rear sight mechanism is here shown at 9 mounted on a rifle comprising a wooden stock portion 1, a metal frame or receiver 2, and barrel 3 having the front sight 4 fixed thereto. The rear sight elevation slide 171 is a vertically slidable member almost square in outline mounted in a T-slot shaped guideway (as shown in Fig. 3) upon an upstanding integral part 2 of the receiver 2. The T-slot guideway is formedby grooves 3 and 3 on opposite sides of the vertical and spaced 70 walls 2 integral with the receiver. In this way a very rigid support for the moving parts of the sight is provided, and this support will serve to protect the sight from injury should the gun be accidentally dropped on its back. The T-slot guideway (indicated at 3') may be slightly inclined from a true vertical line to compensate for the drift of the bullet, and extends above the sighting axis at ordinary ranges as will be seen from Fig. 4. Preferably, the said T-slot guideway is symmetrically disposed at each side of the said sighting axis as will be seen from the drawings. The elevation slide ,Aisformed with an oval-shaped window lopening 172 in front of which is transversely slidable a windage slide 173 carrying the peep hole or rear sight proper 174 and a zero mark in line therewith. A graduated windage scalel is marked on the upper'ledge of the window 172 to register with said Zero mark. The windage slide has a tongue and groove guiding engagement with the upper part of the slide 171 and is housed entirely therein. The said windg e slide is adjustable transverggly of the slidTlmbymeais of t e w' ge we'sligkwittetl''t e lower e(msalmwiiidagslidcasslwhmihwFig. 4. The windage screw has a kurled finger knob 177 at one end, extends through suit- 100 able bearing holes in the slide 171 and has a head 178 at its other end for being held against transverse movement by a spring pressed retaining plunger 179 housed in the slide 171. By pressing the plunger 179 inwardly, the windage screw may be disengaged therefrom and unsc-rewed from the windage slide 173 to release the latter for disassembly.

The vertical adjustment or elevation of the slide 171 is effected by the sight-nut 18() which is rotatably mounted in a lower opening through the slide upon a hollow spindle 181. The periphery of the sight-nut is formed with a plurality of parallel helically disposed ribs 182 in the form of a multiple screw thread adapted to mesh with the teeth of a vertical rack 183 mounted in the receiver. The pitch of the screw threads 182 is sufficient to give the desired eXtreme elevation of the slide with something less than one complete revolution of the nut 180. The upper side of the sightnut is marked with radial lines of a scale 184 for registering with a zero line 185 on the slide to thus indicate the range to which the sight is adjusted.

The rack 183 is preferably cylindrical with a reduced lower end 186 for threaded engagement with the receiver 2. The teeth of the rack are, of course, helically disposed to conform to the pitch of the threads 182, but eX- tend only part way around the cylindrical body of the rack as shown in Fig. 4. The upper end of the rack has a screw driver slot by which it may be partially rotated and vertically adjusted on its screw threaded base 186. A jam screw 187 screw threaded into the receiver bears against one side of the rack 183 for locking it in its adjusted position.

A rotatable adjustment of rack 183 will elevate or lower the sight-nut 180 and slide 171 without disturbing the zero position of the sight nut. This is of advantage in modifying the relations between the front and rear sight for battle sight range or with the rear sight at Zero elevation, which becomes necessary in Calibrating the sight to the particular gun on which it is used. It will be understood that this adjustment or calibration is generally a permanent one and intended to endure for the life of the gun or at least the barrel. Its purpose is to avoid the necessity of sending the gun back to the factory to have the zero positions of the front and rear sights calibrated every time a new barrel is mounted. The amount of rotation for the rack 183 necessary for such an adjustment is very slight and due to the coarse pitch of the threads, here disclosed, a partial rotation of the rack 183 will usually be found sufficient. Any rotation of rack 183 also moves itself vertically on its screwed base 186 and by making the screw threads at 186 of opposite or of the same hand as the pitch of threads 182, a relatively coarse or fine adjustment of the parts may be obtained.

The hollow spindle 181 for the sight-nut 180 is shown in detail in Fig. 7 and has bearings at its upper and lower ends in ledges of the slide 171. From the lower end of spindle 181 projects laterally a detent 188 which works through a key hole slot 193 in the lower ledge 171 of the slide (as shown in Fig. 5) and is pressed into engagement with positioning notches 189 on the under side of the sight nut 180 by a spring 190. The spring 190 is housed in the hollow spindle 181 and seated upon the shoulder of a key-like stem 191 which serves to lock the spindle and its spring in functioning position. The k-ey stem 191 has projecting key lugs 192 spaced apart and adapted, when in operative position, to strad-dle a thinned out portion of the lower ledge 171 of the slide 171, as shown in Fig. 5. In this view only the lower key lug 192 is visible, the upper key lug being at the upper side of the aforementioned ledge. When thus in position, the k-ey stem 191 is anchored to the slide 171.

In order to assemble these parts, the spring 190 is placed over the upper end of the stem 191 and together they are inserted into the hollow spindle 181 with the key lugs 192 projecting through the slot 188 at one side of said spindle. Then these parts are thrust upwardly through the bearing holes of the ledges in the slide 171 and also threaded through the si ght-nut 180 which should be in its place. When first inserted as described, the detent 188 will be diametrically opposite to its position, as shown in Fig. 5, and the key lugs 192 likewise so that the latter may be inserted in the key hole 193. Then after the key lugs 192 are in straddling relation to the ledge 171 adjacent said key hole 193, the stem 191 with the spindle 181 are rotated 18()Q to bring them into the position shown in Fig. 5, whereupon the detent' 188 snaps into the key hole 193 which is its working position for engaging the notches 189 on the under side of the sight-nut 180, see Fig. 5. The positioning notches 189 beneath the nut 180 are made to correspond to the several graduation lines in the scale 184. Therefore, the nut 180 is firmly held in each position of adjustment. A downward pressure on the top of spindle 181 will Adisengage the detent 188 for easy turning of the sight-nut. The nut 180 is limited to slightly less than a full revolution by a stop pin 1931 thereon engageable by the shoulder of detent 188. In order to disassemble the slide 171 and sight-nut 180 from the support, the spindle 181 is depressed far enough to carry the detent shoulder below the stop pin 1931 of the nut 180. Then said nut may be turned off the rack, carrying the slide with it.

The key-stem 191 fixed to the elevation slide extends downwardly into a well hole through the receiver screw 194 and lock nut 195 and engages the upper end of a spring pressed plunger 196. This plunger 196 is backed up by a spring 197 housed in the trigger guard bushing 198 and extends partly through the receiver screw 194 to meet the lower end of the key-stem 191. In this way, a constant upward tension from spring 197 is imposed on the key stem 191 and the elevation slide to which it is fixed, thereby eliminating all loose play or slack in the slide bearings and connections. The screw 194 serves to fasten the rear end of the receiver 2 to the stock 1 by its threaded engagement with the bushing 198 of the trigger guard. The arrangement described provides the necessary tension on the movable parts of the rear sight and yet permits easy removal of the sight Without disturbing the receiver fastening means.

Claims:

1. A rear sight mechanism for small arms comprising in combination, a gun frame having at each side of its longitudinal axis a rigid portion projecting upwardly from the top of said frame, which portions provide a vertical supporting guideway, sight adjusting means comprising an elevational slide mounted on said guideway, a vertically disposed rack on said gun frame, and a peripherally threaded thumb nut carried by said slide and meshing with said rack at one side thereof and exposed for operation by the fingers at ,the p ther side thereof.

"/21 A`rs`iglt mechanism for small arms comprising in combination, a gun frame having at eac-h side of its longitudinal axis a rigid portion projecting upwardly from the top of said frame, which portions provide a vertical supporting guideway, sight adjusting means comprising an elevational slide mounted on said guideway, a vertically disposed rack on said gun frame, and-aperipheall'yhreaded thumb nut carried by said slide and meshing with said rack at one side thereof and exposed for operation by the fingers at the other side thereof, means for imposing a constant vertical spring pressure between said elevational slide and gun frame to take up slack in the connections of said sight adj Listing means.

3. A rear sight mechanism for small arms comprising in combination, a gun frame having at each side of its longitudinal axis a rigid portion projecting upwardly from the top of said frame, which portions provide a vertical supporting guideway, sight adjusting 5 means comprising an elevational slide mounted on said guideway, a vertically disposed rack on said gun frame, said rack being adjustably fixed on said gun frame to raise and lower the Zero position of said elevation slide, and a peripherally threaded thumb nut carried by said slide and meshing with said rack at one side thereof and exposed for operation by the fingers at the other side thereof.

4. A rear sight mechanism for small arms comprising in combination, a gun frame having at each side of its longitudinal axis a rigid portion projecting upwardly from the top of said frame, which portions provide a vertical supporting guideway sight adjusting means comprising an elevational slide mounted on said guideway, a vertically disposed rack on said gun frame, and a peripherally threaded thumb nut carried by said slide and meshing with said rack at one side thereof and exposed for operation by the fingers at the other side thereof, said nut having a beveled top surface and an elevation scale marked there- 5. A rear sight mechanism for small arms comprising in combination, a gun frame having at each side of its longitudinal axis a rigid portion projecting u wardl from the top of said frame, which por lons provide a lerotical supporting guideway, sight adjusting means comprising an elevational slide mountedpnggaid guidewaymially'drack on saidgii frame, a peripherally threaded thumb nut carried by said slide and meshing with said rack at one side thereof and exposed for operation by the fingers at the other side thereof, said nut having a beveled top surface and an elevation scale marked thereon, and a spring pressed finger releasable locking detent for holding said thumb nut in its adjusted positions.

In testimony whereof I have affixed my signature.

JOHN D. PEDERSEN. 

